<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>IFrame-nav</title>
    <style>
        body{
            background-color: #00c0f3;

        }
        ul{
            margin: 0;
            padding: 0;
            list-style: none;
            width: 320px;

        }
        ul li a{
            display: block;
            text-decoration: none;
            color: black;
            background: #b3ecfc;
            padding: 5px;
            border: 1px solid #ccc;
            border-bottom: 0;

        }
        li:hover ul{
            display: block;

        }
        a:hover{
            background-color: #5e9dc9;
        }
    </style>
</head>
<body>
    <ul>
        <li>
            <a href="practice1.html" target="ContentFrame">Courses</a>
        </li>
        <li>
            <a href="Book1.html" target="ContentFrame">MYSQL</a>
        </li>
        <li>
            <a href="Book2.html" target="ContentFrame">MYSQL</a>
        </li>
        <li>
            <a href="Book3.html" target="ContentFrame">MYSQL</a>
        </li>
    </ul>
</body>
</html>